I think you require a thorough ultrasonography
scan of your abdomen, as the symptoms of pain near belly button and a referred pain
in back near shoulder blade are related to gall bladder
Three things support the above facts, 1. You are in good shape (mid obese
) 2. your age is between 35- 40 3. referred pain in back.
You can review with your report to a nearby General Physician, if its normal than there is no need to worry.
hope my info helped you
Dr Hari Om Chandrakar